X-Git-Url: http://plrg.eecs.uci.edu/git/?p=oota-llvm.git;a=blobdiff_plain;f=lib%2FMC%2FMCParser%2FELFAsmParser.cpp;h=e3585bd276327f72e6096524e0b2a0f60b95aeaa;hp=87126f0e3ed2032ffe417426c72a6159efd8854d;hb=cd52a7a381a73c53ec4ef517ad87f19808cb1a28;hpb=68ca56285f9b6e82eb16ff8ea02a301f2c489fae

diff --git a/lib/MC/MCParser/ELFAsmParser.cpp b/lib/MC/MCParser/ELFAsmParser.cpp
index 87126f0e3ed..e3585bd2763 100644
--- a/lib/MC/MCParser/ELFAsmParser.cpp
+++ b/lib/MC/MCParser/ELFAsmParser.cpp
@@ -16,64 +16,65 @@
 #include "llvm/MC/MCParser/MCAsmLexer.h"
 #include "llvm/MC/MCSectionELF.h"
 #include "llvm/MC/MCStreamer.h"
+#include "llvm/MC/MCSymbolELF.h"
 #include "llvm/Support/ELF.h"
 using namespace llvm;
 
 namespace {
 
 class ELFAsmParser : public MCAsmParserExtension {
-  template<bool (ELFAsmParser::*Handler)(StringRef, SMLoc)>
-  void AddDirectiveHandler(StringRef Directive) {
-    getParser().AddDirectiveHandler(this, Directive,
-                                    HandleDirective<ELFAsmParser, Handler>);
+  template<bool (ELFAsmParser::*HandlerMethod)(StringRef, SMLoc)>
+  void addDirectiveHandler(StringRef Directive) {
+    MCAsmParser::ExtensionDirectiveHandler Handler = std::make_pair(
+        this, HandleDirective<ELFAsmParser, HandlerMethod>);
+
+    getParser().addDirectiveHandler(Directive, Handler);
   }
 
-  bool ParseSectionSwitch(StringRef Section, unsigned Type,
-                          unsigned Flags, SectionKind Kind);
-  bool SeenIdent;
+  bool ParseSectionSwitch(StringRef Section, unsigned Type, unsigned Flags,
+                          SectionKind Kind);
 
 public:
-  ELFAsmParser() : SeenIdent(false) {
-    BracketExpressionsSupported = true;
-  }
+  ELFAsmParser() { BracketExpressionsSupported = true; }
 
-  virtual void Initialize(MCAsmParser &Parser) {
+  void Initialize(MCAsmParser &Parser) override {
     // Call the base implementation.
     this->MCAsmParserExtension::Initialize(Parser);
 
-    AddDirectiveHandler<&ELFAsmParser::ParseSectionDirectiveData>(".data");
-    AddDirectiveHandler<&ELFAsmParser::ParseSectionDirectiveText>(".text");
-    AddDirectiveHandler<&ELFAsmParser::ParseSectionDirectiveBSS>(".bss");
-    AddDirectiveHandler<&ELFAsmParser::ParseSectionDirectiveRoData>(".rodata");
-    AddDirectiveHandler<&ELFAsmParser::ParseSectionDirectiveTData>(".tdata");
-    AddDirectiveHandler<&ELFAsmParser::ParseSectionDirectiveTBSS>(".tbss");
-    AddDirectiveHandler<
+    addDirectiveHandler<&ELFAsmParser::ParseSectionDirectiveData>(".data");
+    addDirectiveHandler<&ELFAsmParser::ParseSectionDirectiveText>(".text");
+    addDirectiveHandler<&ELFAsmParser::ParseSectionDirectiveBSS>(".bss");
+    addDirectiveHandler<&ELFAsmParser::ParseSectionDirectiveRoData>(".rodata");
+    addDirectiveHandler<&ELFAsmParser::ParseSectionDirectiveTData>(".tdata");
+    addDirectiveHandler<&ELFAsmParser::ParseSectionDirectiveTBSS>(".tbss");
+    addDirectiveHandler<
       &ELFAsmParser::ParseSectionDirectiveDataRel>(".data.rel");
-    AddDirectiveHandler<
+    addDirectiveHandler<
       &ELFAsmParser::ParseSectionDirectiveDataRelRo>(".data.rel.ro");
-    AddDirectiveHandler<
+    addDirectiveHandler<
       &ELFAsmParser::ParseSectionDirectiveDataRelRoLocal>(".data.rel.ro.local");
-    AddDirectiveHandler<
+    addDirectiveHandler<
       &ELFAsmParser::ParseSectionDirectiveEhFrame>(".eh_frame");
-    AddDirectiveHandler<&ELFAsmParser::ParseDirectiveSection>(".section");
-    AddDirectiveHandler<
+    addDirectiveHandler<&ELFAsmParser::ParseDirectiveSection>(".section");
+    addDirectiveHandler<
       &ELFAsmParser::ParseDirectivePushSection>(".pushsection");
-    AddDirectiveHandler<&ELFAsmParser::ParseDirectivePopSection>(".popsection");
-    AddDirectiveHandler<&ELFAsmParser::ParseDirectiveSize>(".size");
-    AddDirectiveHandler<&ELFAsmParser::ParseDirectivePrevious>(".previous");
-    AddDirectiveHandler<&ELFAsmParser::ParseDirectiveType>(".type");
-    AddDirectiveHandler<&ELFAsmParser::ParseDirectiveIdent>(".ident");
-    AddDirectiveHandler<&ELFAsmParser::ParseDirectiveSymver>(".symver");
-    AddDirectiveHandler<&ELFAsmParser::ParseDirectiveVersion>(".version");
-    AddDirectiveHandler<&ELFAsmParser::ParseDirectiveWeakref>(".weakref");
-    AddDirectiveHandler<&ELFAsmParser::ParseDirectiveSymbolAttribute>(".weak");
-    AddDirectiveHandler<&ELFAsmParser::ParseDirectiveSymbolAttribute>(".local");
-    AddDirectiveHandler<
+    addDirectiveHandler<&ELFAsmParser::ParseDirectivePopSection>(".popsection");
+    addDirectiveHandler<&ELFAsmParser::ParseDirectiveSize>(".size");
+    addDirectiveHandler<&ELFAsmParser::ParseDirectivePrevious>(".previous");
+    addDirectiveHandler<&ELFAsmParser::ParseDirectiveType>(".type");
+    addDirectiveHandler<&ELFAsmParser::ParseDirectiveIdent>(".ident");
+    addDirectiveHandler<&ELFAsmParser::ParseDirectiveSymver>(".symver");
+    addDirectiveHandler<&ELFAsmParser::ParseDirectiveVersion>(".version");
+    addDirectiveHandler<&ELFAsmParser::ParseDirectiveWeakref>(".weakref");
+    addDirectiveHandler<&ELFAsmParser::ParseDirectiveSymbolAttribute>(".weak");
+    addDirectiveHandler<&ELFAsmParser::ParseDirectiveSymbolAttribute>(".local");
+    addDirectiveHandler<
       &ELFAsmParser::ParseDirectiveSymbolAttribute>(".protected");
-    AddDirectiveHandler<
+    addDirectiveHandler<
       &ELFAsmParser::ParseDirectiveSymbolAttribute>(".internal");
-    AddDirectiveHandler<
+    addDirectiveHandler<
       &ELFAsmParser::ParseDirectiveSymbolAttribute>(".hidden");
+    addDirectiveHandler<&ELFAsmParser::ParseDirectiveSubsection>(".subsection");
   }
 
   // FIXME: Part of this logic is duplicated in the MCELFStreamer. What is
@@ -145,9 +146,12 @@ public:
   bool ParseDirectiveVersion(StringRef, SMLoc);
   bool ParseDirectiveWeakref(StringRef, SMLoc);
   bool ParseDirectiveSymbolAttribute(StringRef, SMLoc);
+  bool ParseDirectiveSubsection(StringRef, SMLoc);
 
 private:
   bool ParseSectionName(StringRef &SectionName);
+  bool ParseSectionArguments(bool IsPush, SMLoc loc);
+  unsigned parseSunStyleSectionFlags();
 };
 
 }
@@ -167,10 +171,10 @@ bool ELFAsmParser::ParseDirectiveSymbolAttribute(StringRef Directive, SMLoc) {
     for (;;) {
       StringRef Name;
 
-      if (getParser().ParseIdentifier(Name))
+      if (getParser().parseIdentifier(Name))
         return TokError("expected identifier in directive");
 
-      MCSymbol *Sym = getContext().GetOrCreateSymbol(Name);
+      MCSymbol *Sym = getContext().getOrCreateSymbol(Name);
 
       getStreamer().EmitSymbolAttribute(Sym, Attr);
 
@@ -189,40 +193,42 @@ bool ELFAsmParser::ParseDirectiveSymbolAttribute(StringRef Directive, SMLoc) {
 
 bool ELFAsmParser::ParseSectionSwitch(StringRef Section, unsigned Type,
                                       unsigned Flags, SectionKind Kind) {
-  if (getLexer().isNot(AsmToken::EndOfStatement))
-    return TokError("unexpected token in section switching directive");
-  Lex();
+  const MCExpr *Subsection = nullptr;
+  if (getLexer().isNot(AsmToken::EndOfStatement)) {
+    if (getParser().parseExpression(Subsection))
+      return true;
+  }
 
-  getStreamer().SwitchSection(getContext().getELFSection(
-                                Section, Type, Flags, Kind));
+  getStreamer().SwitchSection(getContext().getELFSection(Section, Type, Flags),
+                              Subsection);
 
   return false;
 }
 
 bool ELFAsmParser::ParseDirectiveSize(StringRef, SMLoc) {
   StringRef Name;
-  if (getParser().ParseIdentifier(Name))
+  if (getParser().parseIdentifier(Name))
     return TokError("expected identifier in directive");
-  MCSymbol *Sym = getContext().GetOrCreateSymbol(Name);
+  MCSymbolELF *Sym = cast<MCSymbolELF>(getContext().getOrCreateSymbol(Name));
 
   if (getLexer().isNot(AsmToken::Comma))
     return TokError("unexpected token in directive");
   Lex();
 
   const MCExpr *Expr;
-  if (getParser().ParseExpression(Expr))
+  if (getParser().parseExpression(Expr))
     return true;
 
   if (getLexer().isNot(AsmToken::EndOfStatement))
     return TokError("unexpected token in directive");
 
-  getStreamer().EmitELFSize(Sym, Expr);
+  getStreamer().emitELFSize(Sym, Expr);
   return false;
 }
 
 bool ELFAsmParser::ParseSectionName(StringRef &SectionName) {
   // A section name can contain -, so we cannot just use
-  // ParseIdentifier.
+  // parseIdentifier.
   SMLoc FirstLoc = getLexer().getLoc();
   unsigned Size = 0;
 
@@ -233,7 +239,6 @@ bool ELFAsmParser::ParseSectionName(StringRef &SectionName) {
   }
 
   for (;;) {
-    StringRef Tmp;
     unsigned CurSize;
 
     SMLoc PrevLoc = getLexer().getLoc();
@@ -263,22 +268,17 @@ bool ELFAsmParser::ParseSectionName(StringRef &SectionName) {
   return false;
 }
 
-static SectionKind computeSectionKind(unsigned Flags) {
-  if (Flags & ELF::SHF_EXECINSTR)
-    return SectionKind::getText();
-  if (Flags & ELF::SHF_TLS)
-    return SectionKind::getThreadData();
-  return SectionKind::getDataRel();
-}
-
-static int parseSectionFlags(StringRef flagsStr) {
-  int flags = 0;
+static unsigned parseSectionFlags(StringRef flagsStr, bool *UseLastGroup) {
+  unsigned flags = 0;
 
   for (unsigned i = 0; i < flagsStr.size(); i++) {
     switch (flagsStr[i]) {
     case 'a':
       flags |= ELF::SHF_ALLOC;
       break;
+    case 'e':
+      flags |= ELF::SHF_EXCLUDE;
+      break;
     case 'x':
       flags |= ELF::SHF_EXECINSTR;
       break;
@@ -303,18 +303,51 @@ static int parseSectionFlags(StringRef flagsStr) {
     case 'G':
       flags |= ELF::SHF_GROUP;
       break;
+    case '?':
+      *UseLastGroup = true;
+      break;
     default:
-      return -1;
+      return -1U;
     }
   }
 
   return flags;
 }
 
+unsigned ELFAsmParser::parseSunStyleSectionFlags() {
+  unsigned flags = 0;
+  while (getLexer().is(AsmToken::Hash)) {
+    Lex(); // Eat the #.
+
+    if (!getLexer().is(AsmToken::Identifier))
+      return -1U;
+
+    StringRef flagId = getTok().getIdentifier();
+    if (flagId == "alloc")
+      flags |= ELF::SHF_ALLOC;
+    else if (flagId == "execinstr")
+      flags |= ELF::SHF_EXECINSTR;
+    else if (flagId == "write")
+      flags |= ELF::SHF_WRITE;
+    else if (flagId == "tls")
+      flags |= ELF::SHF_TLS;
+    else
+      return -1U;
+
+    Lex(); // Eat the flag.
+
+    if (!getLexer().is(AsmToken::Comma))
+        break;
+    Lex(); // Eat the comma.
+  }
+  return flags;
+}
+
+
 bool ELFAsmParser::ParseDirectivePushSection(StringRef s, SMLoc loc) {
   getStreamer().PushSection();
 
-  if (ParseDirectiveSection(s, loc)) {
+  if (ParseSectionArguments(/*IsPush=*/true, loc)) {
     getStreamer().PopSection();
     return true;
   }
@@ -329,7 +362,11 @@ bool ELFAsmParser::ParseDirectivePopSection(StringRef, SMLoc) {
 }
 
 // FIXME: This is a work in progress.
-bool ELFAsmParser::ParseDirectiveSection(StringRef, SMLoc) {
+bool ELFAsmParser::ParseDirectiveSection(StringRef, SMLoc loc) {
+  return ParseSectionArguments(/*IsPush=*/false, loc);
+}
+
+bool ELFAsmParser::ParseSectionArguments(bool IsPush, SMLoc loc) {
   StringRef SectionName;
 
   if (ParseSectionName(SectionName))
@@ -339,6 +376,10 @@ bool ELFAsmParser::ParseDirectiveSection(StringRef, SMLoc) {
   int64_t Size = 0;
   StringRef GroupName;
   unsigned Flags = 0;
+  const MCExpr *Subsection = nullptr;
+  bool UseLastGroup = false;
+  StringRef UniqueStr;
+  int64_t UniqueID = ~0;
 
   // Set the defaults first.
   if (SectionName == ".fini" || SectionName == ".init" ||
@@ -350,19 +391,36 @@ bool ELFAsmParser::ParseDirectiveSection(StringRef, SMLoc) {
   if (getLexer().is(AsmToken::Comma)) {
     Lex();
 
-    if (getLexer().isNot(AsmToken::String))
-      return TokError("expected string in directive");
+    if (IsPush && getLexer().isNot(AsmToken::String)) {
+      if (getParser().parseExpression(Subsection))
+        return true;
+      if (getLexer().isNot(AsmToken::Comma))
+        goto EndStmt;
+      Lex();
+    }
 
-    StringRef FlagsStr = getTok().getStringContents();
-    Lex();
+    unsigned extraFlags;
 
-    int extraFlags = parseSectionFlags(FlagsStr);
-    if (extraFlags < 0)
+    if (getLexer().isNot(AsmToken::String)) {
+      if (!getContext().getAsmInfo()->usesSunStyleELFSectionSwitchSyntax()
+          || getLexer().isNot(AsmToken::Hash))
+        return TokError("expected string in directive");
+      extraFlags = parseSunStyleSectionFlags();
+    } else {
+      StringRef FlagsStr = getTok().getStringContents();
+      Lex();
+      extraFlags = parseSectionFlags(FlagsStr, &UseLastGroup);
+    }
+
+    if (extraFlags == -1U)
       return TokError("unknown flag");
     Flags |= extraFlags;
 
     bool Mergeable = Flags & ELF::SHF_MERGE;
     bool Group = Flags & ELF::SHF_GROUP;
+    if (Group && UseLastGroup)
+      return TokError("Section cannot specifiy a group name while also acting "
+                      "as a member of the last group");
 
     if (getLexer().isNot(AsmToken::Comma)) {
       if (Mergeable)
@@ -371,18 +429,21 @@ bool ELFAsmParser::ParseDirectiveSection(StringRef, SMLoc) {
         return TokError("Group section must specify the type");
     } else {
       Lex();
-      if (getLexer().isNot(AsmToken::Percent) && getLexer().isNot(AsmToken::At))
-        return TokError("expected '@' or '%' before type");
+      if (getLexer().is(AsmToken::At) || getLexer().is(AsmToken::Percent) ||
+          getLexer().is(AsmToken::String)) {
+        if (!getLexer().is(AsmToken::String))
+          Lex();
+      } else
+        return TokError("expected '@<type>', '%<type>' or \"<type>\"");
 
-      Lex();
-      if (getParser().ParseIdentifier(TypeName))
+      if (getParser().parseIdentifier(TypeName))
         return TokError("expected identifier in directive");
 
       if (Mergeable) {
         if (getLexer().isNot(AsmToken::Comma))
           return TokError("expected the entry size");
         Lex();
-        if (getParser().ParseAbsoluteExpression(Size))
+        if (getParser().parseAbsoluteExpression(Size))
           return true;
         if (Size <= 0)
           return TokError("entry size must be positive");
@@ -392,26 +453,52 @@ bool ELFAsmParser::ParseDirectiveSection(StringRef, SMLoc) {
         if (getLexer().isNot(AsmToken::Comma))
           return TokError("expected group name");
         Lex();
-        if (getParser().ParseIdentifier(GroupName))
+        if (getParser().parseIdentifier(GroupName))
           return true;
         if (getLexer().is(AsmToken::Comma)) {
           Lex();
           StringRef Linkage;
-          if (getParser().ParseIdentifier(Linkage))
+          if (getParser().parseIdentifier(Linkage))
             return true;
           if (Linkage != "comdat")
             return TokError("Linkage must be 'comdat'");
         }
       }
+      if (getLexer().is(AsmToken::Comma)) {
+        Lex();
+        if (getParser().parseIdentifier(UniqueStr))
+          return TokError("expected identifier in directive");
+        if (UniqueStr != "unique")
+          return TokError("expected 'unique'");
+        if (getLexer().isNot(AsmToken::Comma))
+          return TokError("expected commma");
+        Lex();
+        if (getParser().parseAbsoluteExpression(UniqueID))
+          return true;
+        if (UniqueID < 0)
+          return TokError("unique id must be positive");
+        if (!isUInt<32>(UniqueID) || UniqueID == ~0U)
+          return TokError("unique id is too large");
+      }
     }
   }
 
+EndStmt:
   if (getLexer().isNot(AsmToken::EndOfStatement))
     return TokError("unexpected token in directive");
 
   unsigned Type = ELF::SHT_PROGBITS;
 
-  if (!TypeName.empty()) {
+  if (TypeName.empty()) {
+    if (SectionName.startswith(".note"))
+      Type = ELF::SHT_NOTE;
+    else if (SectionName == ".init_array")
+      Type = ELF::SHT_INIT_ARRAY;
+    else if (SectionName == ".fini_array")
+      Type = ELF::SHT_FINI_ARRAY;
+    else if (SectionName == ".preinit_array")
+      Type = ELF::SHT_PREINIT_ARRAY;
+  } else {
     if (TypeName == "init_array")
       Type = ELF::SHT_INIT_ARRAY;
     else if (TypeName == "fini_array")
@@ -430,63 +517,103 @@ bool ELFAsmParser::ParseDirectiveSection(StringRef, SMLoc) {
       return TokError("unknown section type");
   }
 
-  SectionKind Kind = computeSectionKind(Flags);
-  getStreamer().SwitchSection(getContext().getELFSection(SectionName, Type,
-                                                         Flags, Kind, Size,
-                                                         GroupName));
+  if (UseLastGroup) {
+    MCSectionSubPair CurrentSection = getStreamer().getCurrentSection();
+    if (const MCSectionELF *Section =
+            cast_or_null<MCSectionELF>(CurrentSection.first))
+      if (const MCSymbol *Group = Section->getGroup()) {
+        GroupName = Group->getName();
+        Flags |= ELF::SHF_GROUP;
+      }
+  }
+
+  MCSection *ELFSection = getContext().getELFSection(SectionName, Type, Flags,
+                                                     Size, GroupName, UniqueID);
+  getStreamer().SwitchSection(ELFSection, Subsection);
+
+  if (getContext().getGenDwarfForAssembly()) {
+    bool InsertResult = getContext().addGenDwarfSection(ELFSection);
+    if (InsertResult) {
+      if (getContext().getDwarfVersion() <= 2)
+        Warning(loc, "DWARF2 only supports one section per compilation unit");
+
+      if (!ELFSection->getBeginSymbol()) {
+        MCSymbol *SectionStartSymbol = getContext().createTempSymbol();
+        getStreamer().EmitLabel(SectionStartSymbol);
+        ELFSection->setBeginSymbol(SectionStartSymbol);
+      }
+    }
+  }
+
   return false;
 }
 
 bool ELFAsmParser::ParseDirectivePrevious(StringRef DirName, SMLoc) {
-  const MCSection *PreviousSection = getStreamer().getPreviousSection();
-  if (PreviousSection == NULL)
+  MCSectionSubPair PreviousSection = getStreamer().getPreviousSection();
+  if (PreviousSection.first == nullptr)
       return TokError(".previous without corresponding .section");
-  getStreamer().SwitchSection(PreviousSection);
+  getStreamer().SwitchSection(PreviousSection.first, PreviousSection.second);
 
   return false;
 }
 
+static MCSymbolAttr MCAttrForString(StringRef Type) {
+  return StringSwitch<MCSymbolAttr>(Type)
+          .Cases("STT_FUNC", "function", MCSA_ELF_TypeFunction)
+          .Cases("STT_OBJECT", "object", MCSA_ELF_TypeObject)
+          .Cases("STT_TLS", "tls_object", MCSA_ELF_TypeTLS)
+          .Cases("STT_COMMON", "common", MCSA_ELF_TypeCommon)
+          .Cases("STT_NOTYPE", "notype", MCSA_ELF_TypeNoType)
+          .Cases("STT_GNU_IFUNC", "gnu_indirect_function",
+                 MCSA_ELF_TypeIndFunction)
+          .Case("gnu_unique_object", MCSA_ELF_TypeGnuUniqueObject)
+          .Default(MCSA_Invalid);
+}
+
 /// ParseDirectiveELFType
+///  ::= .type identifier , STT_<TYPE_IN_UPPER_CASE>
+///  ::= .type identifier , #attribute
 ///  ::= .type identifier , @attribute
+///  ::= .type identifier , %attribute
+///  ::= .type identifier , "attribute"
 bool ELFAsmParser::ParseDirectiveType(StringRef, SMLoc) {
   StringRef Name;
-  if (getParser().ParseIdentifier(Name))
+  if (getParser().parseIdentifier(Name))
     return TokError("expected identifier in directive");
 
   // Handle the identifier as the key symbol.
-  MCSymbol *Sym = getContext().GetOrCreateSymbol(Name);
+  MCSymbol *Sym = getContext().getOrCreateSymbol(Name);
+
+  // NOTE the comma is optional in all cases.  It is only documented as being
+  // optional in the first case, however, GAS will silently treat the comma as
+  // optional in all cases.  Furthermore, although the documentation states that
+  // the first form only accepts STT_<TYPE_IN_UPPER_CASE>, in reality, GAS
+  // accepts both the upper case name as well as the lower case aliases.
+  if (getLexer().is(AsmToken::Comma))
+    Lex();
 
-  if (getLexer().isNot(AsmToken::Comma))
-    return TokError("unexpected token in '.type' directive");
-  Lex();
+  if (getLexer().isNot(AsmToken::Identifier) &&
+      getLexer().isNot(AsmToken::Hash) && getLexer().isNot(AsmToken::At) &&
+      getLexer().isNot(AsmToken::Percent) && getLexer().isNot(AsmToken::String))
+    return TokError("expected STT_<TYPE_IN_UPPER_CASE>, '#<type>', '@<type>', "
+                    "'%<type>' or \"<type>\"");
 
-  if (getLexer().isNot(AsmToken::Percent) && getLexer().isNot(AsmToken::At))
-    return TokError("expected '@' or '%' before type");
-  Lex();
+  if (getLexer().isNot(AsmToken::String) &&
+      getLexer().isNot(AsmToken::Identifier))
+    Lex();
 
-  StringRef Type;
-  SMLoc TypeLoc;
+  SMLoc TypeLoc = getLexer().getLoc();
 
-  TypeLoc = getLexer().getLoc();
-  if (getParser().ParseIdentifier(Type))
+  StringRef Type;
+  if (getParser().parseIdentifier(Type))
     return TokError("expected symbol type in directive");
 
-  MCSymbolAttr Attr = StringSwitch<MCSymbolAttr>(Type)
-    .Case("function", MCSA_ELF_TypeFunction)
-    .Case("object", MCSA_ELF_TypeObject)
-    .Case("tls_object", MCSA_ELF_TypeTLS)
-    .Case("common", MCSA_ELF_TypeCommon)
-    .Case("notype", MCSA_ELF_TypeNoType)
-    .Case("gnu_unique_object", MCSA_ELF_TypeGnuUniqueObject)
-    .Case("gnu_indirect_function", MCSA_ELF_TypeIndFunction)
-    .Default(MCSA_Invalid);
-
+  MCSymbolAttr Attr = MCAttrForString(Type);
   if (Attr == MCSA_Invalid)
     return Error(TypeLoc, "unsupported attribute in '.type' directive");
 
   if (getLexer().isNot(AsmToken::EndOfStatement))
     return TokError("unexpected token in '.type' directive");
-
   Lex();
 
   getStreamer().EmitSymbolAttribute(Sym, Attr);
@@ -504,22 +631,7 @@ bool ELFAsmParser::ParseDirectiveIdent(StringRef, SMLoc) {
 
   Lex();
 
-  const MCSection *Comment =
-    getContext().getELFSection(".comment", ELF::SHT_PROGBITS,
-                               ELF::SHF_MERGE |
-                               ELF::SHF_STRINGS,
-                               SectionKind::getReadOnly(),
-                               1, "");
-
-  getStreamer().PushSection();
-  getStreamer().SwitchSection(Comment);
-  if (!SeenIdent) {
-    getStreamer().EmitIntValue(0, 1);
-    SeenIdent = true;
-  }
-  getStreamer().EmitBytes(Data);
-  getStreamer().EmitIntValue(0, 1);
-  getStreamer().PopSection();
+  getStreamer().EmitIdent(Data);
   return false;
 }
 
@@ -527,24 +639,31 @@ bool ELFAsmParser::ParseDirectiveIdent(StringRef, SMLoc) {
 ///  ::= .symver foo, bar2@zed
 bool ELFAsmParser::ParseDirectiveSymver(StringRef, SMLoc) {
   StringRef Name;
-  if (getParser().ParseIdentifier(Name))
+  if (getParser().parseIdentifier(Name))
     return TokError("expected identifier in directive");
 
   if (getLexer().isNot(AsmToken::Comma))
     return TokError("expected a comma");
 
+  // ARM assembly uses @ for a comment...
+  // except when parsing the second parameter of the .symver directive.
+  // Force the next symbol to allow @ in the identifier, which is
+  // required for this directive and then reset it to its initial state.
+  const bool AllowAtInIdentifier = getLexer().getAllowAtInIdentifier();
+  getLexer().setAllowAtInIdentifier(true);
   Lex();
+  getLexer().setAllowAtInIdentifier(AllowAtInIdentifier);
 
   StringRef AliasName;
-  if (getParser().ParseIdentifier(AliasName))
+  if (getParser().parseIdentifier(AliasName))
     return TokError("expected identifier in directive");
 
   if (AliasName.find('@') == StringRef::npos)
     return TokError("expected a '@' in the name");
 
-  MCSymbol *Alias = getContext().GetOrCreateSymbol(AliasName);
-  MCSymbol *Sym = getContext().GetOrCreateSymbol(Name);
-  const MCExpr *Value = MCSymbolRefExpr::Create(Sym, getContext());
+  MCSymbol *Alias = getContext().getOrCreateSymbol(AliasName);
+  MCSymbol *Sym = getContext().getOrCreateSymbol(Name);
+  const MCExpr *Value = MCSymbolRefExpr::create(Sym, getContext());
 
   getStreamer().EmitAssignment(Alias, Value);
   return false;
@@ -560,9 +679,7 @@ bool ELFAsmParser::ParseDirectiveVersion(StringRef, SMLoc) {
 
   Lex();
 
-  const MCSection *Note =
-    getContext().getELFSection(".note", ELF::SHT_NOTE, 0,
-                               SectionKind::getReadOnly());
+  MCSection *Note = getContext().getELFSection(".note", ELF::SHT_NOTE, 0);
 
   getStreamer().PushSection();
   getStreamer().SwitchSection(Note);
@@ -582,7 +699,7 @@ bool ELFAsmParser::ParseDirectiveWeakref(StringRef, SMLoc) {
   // FIXME: Share code with the other alias building directives.
 
   StringRef AliasName;
-  if (getParser().ParseIdentifier(AliasName))
+  if (getParser().parseIdentifier(AliasName))
     return TokError("expected identifier in directive");
 
   if (getLexer().isNot(AsmToken::Comma))
@@ -591,17 +708,31 @@ bool ELFAsmParser::ParseDirectiveWeakref(StringRef, SMLoc) {
   Lex();
 
   StringRef Name;
-  if (getParser().ParseIdentifier(Name))
+  if (getParser().parseIdentifier(Name))
     return TokError("expected identifier in directive");
 
-  MCSymbol *Alias = getContext().GetOrCreateSymbol(AliasName);
+  MCSymbol *Alias = getContext().getOrCreateSymbol(AliasName);
 
-  MCSymbol *Sym = getContext().GetOrCreateSymbol(Name);
+  MCSymbol *Sym = getContext().getOrCreateSymbol(Name);
 
   getStreamer().EmitWeakReference(Alias, Sym);
   return false;
 }
 
+bool ELFAsmParser::ParseDirectiveSubsection(StringRef, SMLoc) {
+  const MCExpr *Subsection = nullptr;
+  if (getLexer().isNot(AsmToken::EndOfStatement)) {
+    if (getParser().parseExpression(Subsection))
+     return true;
+  }
+
+  if (getLexer().isNot(AsmToken::EndOfStatement))
+    return TokError("unexpected token in directive");
+
+  getStreamer().SubSection(Subsection);
+  return false;
+}
+
 namespace llvm {
 
 MCAsmParserExtension *createELFAsmParser() {